Vector sensors measure scalar pressure and acoustic particle velocity of sound waves. In contrast to conventional omnidirectional hydrophones, vector sensors are capable of providing directivity information. U.S. Pat. No. 4,827,459 proposed an accelerometer for use in underwater acoustic sensors. The accelerometer includes a pair of piezoelectric crystals capable of generating orthogonal voltage signals in response to translational motion of the acoustic sensor, from which signals crossed dipole directivity patterns can be obtained.
Miniaturization of vector sensors can pose challenges relating to physical arrangement of sensor components, control of resonance effects and reducing the density of the sensor.
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